Many shipping containers for hazardous materials are conventionally designed as single use packages to be sent to a purchaser in the form of a sealed secure package without provision for positive reclosure upon reuse or return. Shipping container construction having one-time positive closure means is exemplified by a metal canister with a soldered or seamed-on cover. The act of opening these types of covers destroys the positive closure feature of the container and makes it unsuitable for return shipment of hazardous materials.
Department of Transportation Regulation Title 49 for pyrophoric liquids, NOS (not otherwise specified) sections 173.134(a) (2) and (a) (3) set out the requirements for shipping small quantities of pyrophoric liquids. The regulation specifies in (a) (2) that certain wooden or fiber board boxes enclosing strong tight metal cans with glass or metal not over one quart capacity and in (a) (3) metal drums not over 1 gallon capacity, constructed of not less than 28 gauge electro-coated tin plate are to be closed by positive means, not friction.
Electronic chemicals which are pyrophoric liquids such as triethyl aluminum, trimethyl gallium, dimethyl zinc, and triethyl indium are shipped in valved stainless steel strong metal packages packed in cushioning material (e.g., vermiculite) in shipping containers conforming to Section 173.134(a) (2) and (a) (3).
Typically, after customer use, the stainless steel strong metal packages contain residual pyrophoric liquid. The customer must either clean the cylinder or return it to the distributor with the same shipping precautions with which it was sent.
It is desirable to develop a shipping container that may be resealed in a positive manner to permit its return or reuse.